Exercise During Pregnancy for Smaller Baby

April 5, 2010 -- Women who exercise moderately during pregnancy give birth
to somewhat smaller babies, which may reduce the infants' obesity risk later,
according to a new study.

The average birth weight of babies born to exercising mothers was lower but
still very healthy.

The average birth weight of babies born to mothers who exercised was 7.5
pounds, compared to 7.8 pounds for mothers who did not exercise, says a team of
researchers from New Zealand and the U.S. Babies born weighing 8.8 pounds
or more are defined as high birth weight.

At the two-week checkup, the babies of exercising moms averaged 8.1
pounds; the babies of sedentary moms averaged 8.6 pounds.

"We would suggest this study support the recommendations of at least 30
minutes of moderate exercise daily and probably more," says study co-author
Paul Hofman, MD, a researcher at the University of Auckland in New Zealand. The
study is published in the Journal of Clinical Endocrinology &
Metabolism.

The new research follows a
recent study finding that three out of four pregnant women in the U.S. do
not get enough exercise.

Exercise During Pregnancy: The Study

Hofman and his colleagues assigned 84 women pregnant with their first child
to an exercise group or a control group. Women in the exercise group rode
stationary bikes at home at a moderate intensity for 40 minutes, 5 times a week
maximum, beginning at 20 weeks into the pregnancy and continuing until about
week 36.

Women in the control group were instructed to continue their normal daily
activities during the same time periods.

Women in both groups had, on average, a healthy body weight before pregnancy
and were similar in other regards such as age and ethnicity.

Exercise During Pregnancy: Results

The babies born to the exercisers had a lower body weight and a lower body
mass index or BMI.

There were no differences in the length of the babies, on average, between
exercisers and non-exercisers. The exercise didn't affect the length of the
pregnancy, either, or the mothers’ weight.